Presser foot pressure indicating device for sewing machines



y 4, 1968 s. D. LAPOLICE ETAL 3,382,830

PRESSER FOOT PRESSURE INDICATING DEVICE FOR SEWING MACHINES Filed Feb; 6, 1967 INVENTORS George D. LclPolice and Louis F. Duman AT.- O.R.NEY

United States Patent 3,382,830 PRESSER FOOT PRESSURE INDICATING DEVICE FOR SEWING MACHINES George D. La Police, Somerville, and Louis F. Daman,

Martinsville, N.J., assignors to The Singer Company,

New York, N.1., a corporation of New Jersey Filed Feb. 6, 1967, Ser. No. 614,337 7 Claims. (Cl. 112-235) ABSTRACT OF THE DISCLOSURE An apparatus for indicating the pressure exerted by a presser foot against work fabric placed on the work-supporting bed of a sewing machine. A pointer is mounted on a conventional presser bar between the coil spring and the pressure-setting thumbscrew. The pointer protrudes through an elongated vertical aperture in the sewing head and moves upwardly or downwardly when the pressuresetting thumbscrew is moved upwardly or downwardly. The elongated vertical aperture and the end of the pointer are covered by a transparent cap which has vertically oriented indicia to indicate the pressure set by the thumbscrew and exerted by the presser foot.

Background of the invention (1) Field of the invention.-The invention pertains to presser devices for holding work fabric on work-supporting beds of sewing machines and more particularly to presser foot pressure indicating devices for sewing machines.

(2) Description of the prior art-Conventional sewing machines are equipped with presser foot pressure setting and indicating devices housed in the sewing head. The sewing head is provided with apertures to permit portions of the presser foot pressure setting and indicating devices to protrude through the sewing head to allow the operator to view and control the pressure exerted by the presser foot against work fabric placed on the work-supporting bed.

Experience has shown that the foregoing apertures are ready receptacles for dust, dirt, debris, and the like, which clog the apertures and interfere with the mechanisms in the sewing heads. Also, the presser foot pressure indicating indicia are rendered less visible through use, abuse, and normal wear and tear. The presser foot pressure indicators are mishandled by the uninformed, the apertures are not positioned to take full advantage of light conditions in the vicinity of the sewing heads, and the potential aesthetic appeal of the sewing machines is reduced rather than enhanced by the purely utilitarian arrangement of the visible portions of the presser foot pressure indicating devices.

Summary of the invention It is, therefore, an object of the invention to provide an improved presser foot pressure setting and indicating device which is mounted in line on the presser bar.

Another object of the invention is to provide a presser foot pressure indicating device for a sewing machine in which the aperture for the indicating device is closed by a transparent cap.

Another object of the invention is to provide a transparent cap in accordance with the foregoing object in which the transparent cap is readily removable for replacement and assembly purposes.

The invention includes a collar mounted on the presser bar between the coil spring and the pressure-setting thumbscrew. The collar is connected to the thumbscrew by a horseshoe-shaped clip on the collar which projects into an annular groove on the thumbscrew permitting turning of the thumbscrew without rotating the collar. A pointer extends from the collar through an elongated vertical aperture in the face plate. A guide slides against a portion of the inner wall of the sewing head to prevent rotation of the pointer. The elongated vertical aperture in the face plate and the end of the pointer are covered by a transparent cap which is held on the face plate by a U-shaped spring clip. Vertically oriented indicia on the side of the transparent cap register the presser foot pressure set by the thumbscrew and indicated by the pointer. The bottom of the knob of the thumbscrew and the top of the sewing head limit the downward movement of the pointer so that it cannot strike the bottom of the inside of the transparent cap. The top of the collar and the bottom of the portion of the sewing head surrounding the tapped hole for the thumbscrew limit the upward movement of the pointer so that it cannot strike the top of the inside of the transparent cap. The inline arrangement of the presser foot pressure setting and indicating device takes up little room inside the sewing head and makes the invention readily attachable to existing machines. The transparent cap seals the aperture for the indicator, and the transparent cap can easily be replaced if damaged or the indicia become worn.

Other objects and a full understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings in which:

Brief description of the drawings FIG. 1 is a partially sectioned front elevational view of the sewing head end of a sewing machine embodying the invention;

FIG. 2 is a partially sectioned end elevational view of the sewing head end of the sewing machine of FIG. 1;

FIG. 3 is an enlarged exploded perspective view of the presser foot pressure indicator and associated mechanisms;

FIG. 4 is an enlarged exploded perspective view of the transparent cap which covers the pointer of the presser foot pressure indicator; and

FIG. 5 is a perspective view of the transparent cap of FIG. 4 in place on the sewing head.

Description of the preferred embodiment With reference to the drawings, the invention is illustrated as embodied in a conventional sewing machine having a frame which includes a work-supporting bed 11 and a sewing head 12 overhanging the work-supporting bed. The sewing head is located at the free end of a bracket arm 13 which is cantilevered from a vertical standard on the work-supporting bed. The vertical standard is not shown because it forms no part of the invention. It is simply the support for the bracket arm and sewing head. The end of the sewing head is covered by a face plate 14- which is removably fastened to the sewing head by a thumbscrew 15.

Mounted in the work-supporting bed is a feed mechanism represented in the drawings by the feed teeth of a feed dog 16. The feed dog is covered by a throat plate 17 which has slots for the feed teeth. The slots do not show in the drawings.

Mounted in a sleeve 18 in the sewing head is a needle bar 19. Endwise reciprocation is imparted to the needle bar by a suitable mechanism in the bracket arm in timed relation with movement of a complementary loop taker in the work-supporting bed and feed movement of the feed dog. The needle bar mechanism and the loop taker are not shown because they also form no part of the invention. A needle 20 is connected to the end of the needle bar by a thumbscrew 21.

Also mounted in the sewing head is a presser bar 22. The presser bar is mounted in a sleeve 23 in the lower portion of the sewing head. A presser foot 24 is connected to the end of the presser bar by a thumbscrew 25. The presser foot has a shank 26 and a sole plate 27. The sole plate is adapted to oppose the feed teeth of the feed dog 16 by imposing pressure on work fabric as the work fabric is fed by the feed dog across the work-supporting bed.

Also mounted in the sewing head is a hand presser lifter 28. The hand presser lifter is connected to the inner wall of the sewing head by a pivot screw 29. The hand presser lifter includes a hand lever portion 30 and a cam portion 31. The cam portion of the hand presser lifter bears against the bottom surface of a clamp 3-2 which is locked on the presser bar by a set screw 33. The cam portion raises the presser foot 24 when the hand lever is pivoted upwardly.

The presser bar 22 has a reduced portion 34 on which is mounted a compression coil spring 35. The reduced portion forms a shoulder 36 with the remainder of the presser bar. The shoulder acts as stop means to determine the lowermost extent of the compression coil spring, the bottom of which is supported by the shoulder.

Mounted on the reduced portion of the presser bar above the coil spring is indicator means 37 including a cylindrical collar 38. The cylindrical collar has a clearance hole 39 for the reduced portion 34 of the presser bar and a lower hole or counterbore 40 for the compression coil spring. The lower counterbore forms a shoulder 41 around the clearance hole to serve as a seat for the top of the compression coil spring thus sandwiching the compression coil spring between the shoulder on the presser bar and the shoulder on the cylindrical collar. The cylindrical collar also has an upper hole or counterbore 42 and diametrically opposed slots 43 in the wall of the upper counterbore.

Formed in the sewing head above the collar 38 is a shelf 44. Mounted on the shelf is a boss 45. A tapped hole 46 is formed through the boss and the shelf for a thumbscrew 47. The thumbscrew has a threaded intermediate portion 48 by which it is threaded into the tapped hole in the boss and the shelf. A knurled knob 49 is formed at the top of the thumbscrew. The knurled knob has a larger diameter than the threaded intermediate portion of the thumbscrew to form a shoulder 50 between the knurled knob and the threaded intermediate portion.

The thumbscrew also has a reduced portion 51 as its lower extremity. An annular groove 52 is formed in the reduced portion, and a clearance bore 53 is formed in the bottom of the thumbscrew for the upper extremity of the reduced portion 34 of the presser bar. The reduced portion of the thumbscrew fits into the upper counterbore 42 formed in the cylindrical collar 38. The thumbscrew is connected to the collar by fastening means in the form of a U-shaped or horseshoe-shaped clip 54, the arms 55 of which seat in the diametrically opposed slots 43 in the wall of the upper counterbore 42 in the collar. Inwardly pointed hooks 56 formed on the free ends of the arms project into the annular groove 52 to connect the thumbscrew to the collar while permitting rotation of the thumbscrew relative to the collar.

Formed on the bottom extremity of the indicator means or cylindrical collar 38 is a neck portion 57. A pointer 58 is mounted on the neck portion. The pointer is rotatably held on the cylindrical collar by spinning over the bottom of the neck portion to form a flange 59. The pointer protrudes through an elongated vertical aperture 60 formed in the face plate 14 and the free end of the pointer is coated with red paint 61 to increase visibility. The pointer includes a guide portion 62 at a right angle to the pointer. The guide portion slides against the inner wall of the sewing head top reveut rotation of the pointer around the presser bar. The guide portion prevents rotation of the pointer because it has a relatively long straight edge 63 which slides against the inner wall of the sewing head.

An elongated transparent cap 64 covers the free end of the pointer 58. The elongated transparent cap has a reduced portion 65 which seats in the elongated vertical aperture 60 in the face plate. The reduced portion 65 forms a shoulder 66 with the remainder of the transparent cap. A peripheral groove 67 is formed in the reduced portion. The thickness 68 of the reduced portion from the shoulder 66 to the near wall 69 of the peripheral groove 67 is substantially equal to the thickness of the portion of the face plate 14 surrounding the elongated vertical aperture 60.

The transparent cap 64 is held on the face plate by a U-shaped spring clip 76. The U-shaped clip has a base 71 and two arms 72. The free ends of the arms have turned up portions '73 to facilitate insertion into the peripheral groove 67 in the reduced portion 65 of the transparent cap. The base of the U-shaped spring cli also has a turned up portion 74 to provide a finger grip for assembly and disassembly of the spring clip. Indicia 75 in the form of numerals are formed on the side of the transparent cap facing the front of the sewing machine to register presser foot pressure indicated by the pointer 58 as seen through the transparent cap.

In operation, pivotal movement of the hand presser lifter lever 28 upwardly raises the presser foot 24 against the pressure of the compression coil spring 35 because of the camming action of the cam portion 31 of the presser lifter against the clam 32 on the presser bar. Conversely, downward movement of the presser lifter lever lowers the presser foot against Work fabric placed on the worksupporting bed between the sole plate 27 of the presser foot and the feed dog 16. The thumbscrew 47 sets the pressure exerted by the sole late of the presser foot on the work fabric by determining the compression of the coil spring 35. Turning of the thumbscrew to adjust the compression in the coil spring moves the collar 38 and the pointer 58 upwardly or downwardly on the presser bar. The pressure of the presser foot on work fabric can be determined by reading the location of the pointer relative to the numerals 75 on the transparent cap 64. The bottom 50 of the knurled knob 49 and the top of the sewing head determine the lowermost position of the pointer which is always above the bottom or floor of the transparent cap. The top of the collar 38 and the bottom of the shelf 44 surrounding the tapped hole 46 for the thumbscrew determine the uppermost position of the pointer which is always below the top or ceiling of the inside of the transparent cap. The transparent cap can easily be replaced by simply retracting the U-shaped spring clip from the peripheral groove 67 in the reduced portion 65 of the transparent cap.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention.

Having thus set forth the nature of this invention, what is claimed herein is:

1. A presser foot pressure indicating device for a sewing machine having a frame including a work-supporting bed and a sewing head overhanging the work-supporting bed, a presser bar mounted in the sewing head, a presser foot connected to the external extremiy of the presser bar for pressing against the top surface of the work-supporting bed, a coil spring mounted on the presser bar, and stop means at an intermediate por.ion of the presser bar for determining the lowermost extent of the coil spring, said presser foot pressure indicating device comprising said sewing head with an elongated vertical aperture and a horizontally disposed tapped hole formed therein, indicator means mounted on the presser bar at the top of the coil spring and protruding through said elongated vertical aperture formed in said sewing head, a thumbscrew threaded into the horizontally disposed tapped hole in the sewing head at the top of the indicator means to move the indicator means upwardly and downwardly in said elongated vertical aperture, and an elongated transparent cap mounted in said elongated vertical aperture formed in said sewing head to cover the protruding end of the indicator means.

2. The presser foot pressure indicating device of claim 1 in which the indicator means has a guide portion which slides against a portion of the inner wall of the sewing head to prevent rotation of the indicator means around the presser bar.

3. The presser foot pressure indicating device of claim 2 in which the indicator means includes a collar mounted on the presser bar at the top of the coil spring and a substantially horizontal pointer on the collar protruding through the elongated vertical aperture which is formed in the sewing head and one of said collar and thumbscrew has a portion with an annular groove, the other of said collar and thumbscrew has a hole to receive said portion having the annular groove, and fastening means are provided which projects into the annular groove to connect the collar to the thumbscrew while permitting rotation of the thumbscrew relative to the collar.

4. The presser foot pressure indicating device of claim 3 in which said hole has diametrically opposed slots and the fastening means is a U-shaped clip having two arms which seat in the slots and project into the annular groove to connect the thumbscrew to the collar while permitting rotation of the thumbscrew relative to the collar.

5. The presser foot pressure indicating device of claim I in which the thumbscrew has a knob with a larger diameter than the diameter of the threaded portion and the bottom of the knob and the top of the sewing head determine the lowermost position of the pointer and the top of the indicator means and the bottomof the portion of the sewing head surrounding the tapped hole determine the uppermost position of the pointer, said lowermost and uppermost positions above and below the bottom and top, respectively, of the inside of the elongated transparent cap.

6. The presser foot pressure indicating device of claim 1 which includes vertically oriented indicia on the elongated transparent cap to indicate the presser foot pressure.

7. The presser foot pressure indicating device of claim 1 which includes a U-shaped clip and the elongated transparent cap has a reduced portion which seats in the elongated vertical aperture in the sewing head, the reduced portion having a peripheral groove for receiving the U- shaped clip to retain the elongated transparent cap on the sewing head, the thickness of the reduced portion between the shoulder formed by the reduced portion and the near wall of the peripheral groove substantially equal to the thickness of the portion of the sewing head surrounding the elongated vertical aperture.

References Cited UNITED STATES PATENTS 3,089,447 5/1963 Shuman 112235 3,294,047 12/1966 Graham 1l2-235 3,303,804 2/1967 Lesort 112-235 PATRICK D. LAWSON, Primary Examiner. 

